Question

For an arithmetic sequence, given Sn=690,a1=19, an=96 find the value of n help pleaseeeee​

Answer 1

To find the value of n in an arithmetic sequence, use the formula Sn = (n/2)(a1 + an), where Sn is the sum of the first n terms, a1 is the first term, and an is the nth term. In this case, n = 12.

Step-by-step explanation:

To find the value of n in an arithmetic sequence, you can use the formula Sn = (n/2)(a1 + an), where Sn is the sum of the first n terms, a1 is the first term, and an is the nth term.

In this case, the sum Sn is given as 690, the first term a1 is 19, and the nth term an is 96.

Using the formula, we can write the equation 690 = (n/2)(19 + 96), and solve for n.

First, simplify the equation to 690 = (n/2)(115).

Then divide both sides of the equation by 115 to get 6 = n/2.

Multiply both sides by 2 to isolate n, giving you n = 12.